Re: [Help-bash] How to print a bash variable in the most succinct way?

[Peng Yu]

On Tuesday, August 16, 2016, Chet Ramey <address@hidden> wrote:

> On 8/16/16 9:21 PM, Peng Yu wrote:
> > On Tue, Aug 16, 2016 at 8:13 PM, Chet Ramey <address@hidden
> <javascript:;>> wrote:
> >> On 8/16/16 4:54 PM, Peng Yu wrote:
> >>> On Tue, Aug 16, 2016 at 2:56 PM, Chet Ramey <address@hidden
> <javascript:;>> wrote:
> >>>> On 8/16/16 3:21 PM, Peng Yu wrote:
> >>>>
> >>>>>
> >>>>> How to only generate variables that are modifiable (i.e., not
> readonly)?
> >>>>
> >>>> Generate a list of all variables.  Generate a list of readonly
> variables.
> >>>
> >>> How to generate a list of the names of the readonly variables?
> >>> `readonly` will print both the names and their values. I will run into
> >>> the same problem when there are $'\n' in their values.
> >>
> >> Use the toolset.
> >>
> >> readonly -p | grep = | sed 's|^declare.* \([[:upper:][:lower:]_]*\)=.*$
> |\1|'
> >> readonly -p | awk '$0 ~ "declare.*" {print $3}' | sed
> >> 's|[^[:upper:][:lower:]_].*$||'
> >
> > These commands won't work robustly as shown below.
>
> Then modify them.  You have to do some of the work yourself here.


It will requires a parser to parse the result if one wants it to robust. It
can require quite some work.

Are you able to add an option to the cmd readonly so that it can only print
varible names?

>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>                  ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, UTech, CWRU    address@hidden <javascript:;>
> http://cnswww.cns.cwru.edu/~chet/
>


-- 
Regards,
Peng